The present invention relates to a process and a device working by means of a flame for manufacturing a synthesis gas that can for example be used for preparing ammonia, or for manufacturing a reducing gas, particularly for the steel industry.
The ideal production of gas for the synthesis of ammonia is performed according to the following total reaction: EQU C.sub.x H.sub.y +x/2.0.sub.2 +xH.sub.2 O.fwdarw.xCO.sub.2 +(2x+y)/2.H.sub.2
A first method for producing synthesis gas with a good energy yield consists in associating a primary reforming with a secondary reforming.
In primary reforming, a strong overflash (molar ratio H.sub.2 O/C&gt;2) the energy of which is recovered after the secondary reforming is introduced into a reactor comprising a catalyst.
In the secondary (catalytic) reforming, the effluents from the primary reforming are partly burnt while air is
A second method for producing synthesis gas consists in burning in a reactor a fuel in an atmosphere with a lack of oxygen.
The combustion of hydrocarbons, such as methane generally stemming from natural gas, in an atmosphere with a lack of oxygen leads to the forming of carbon monoxide (CO), of hydrogen (H.sub.2) which are the constituents of the synthesis gas, but also of carbon dioxide (CO.sub.2), water (H.sub.2 O) and quite often of soot (C).
Soot notably appears when the lack of oxygen is too considerable. Still, since the yield in potential hydrogen increases, in a first approximation, with the combustion temperature and the lack of air or oxygen, the increase in hydrogen yield goes together with the forming of soot. The combustion temperature notably varies according to the preheating temperature of the fuel and the oxidizer.
Since this soot clogs the production equipments, which is not wished for, steam can be introduced into the reactor in order to prevent the forming of soot. The effluents can also be washed to remove the formed soot. In these two cases, the necessary material investment is very high.
Potential hydrogen means the amounts of hydrogen (H.sub.2) and of carbon monoxide (CO) which are produced by the combustion. The carbon monoxide (CO) can be converted into hydrogen by shift conversion.
French Patent Application FR-2,608,581 describes a process and a device working by means of a flame for the manufacturing of synthesis gas. This process and the working of the device according to this invention, which avoids the presence of soot at the reactor outlet, consists in making the formed soot deposit on more or less deflecting walls located in the waste gas flow (effluents), then in oxidizing this soot by adding some oxidizer across the walls which are porous.